Are Casino Bonuses Worth It? The 5 Numbers That Actually Decide

A casino offers you “£100 free.” Sounds like a yes. But that headline number tells you almost nothing about whether the bonus is actually worth taking. The same “£100 free” can be genuinely good value, completely worthless, or worse than depositing with no bonus at all. The difference is entirely in the small print, and it comes down to five numbers.

Learn these five and you will never be fooled by a big headline again.

1. The bonus amount

The obvious one, and the one casinos want you looking at. It is the free money on the table: £25, £100, £200. On its own it means nothing, because it is the only number in the offer that is working in your favour. The other four decide how much of it you actually keep.

2. The wagering requirement

This is the big one. The wagering requirement is how many times you have to bet the bonus before you can withdraw anything you win with it.

As of 19 January 2026, the UK Gambling Commission caps this at 10x. So a £100 bonus can require at most £1,000 of total betting before withdrawal. Under the old system you might have seen 40x or 50x, which on £100 meant grinding through £4,000 or £5,000. The cap is a real improvement, but 10x is still ten times, and every pound you wager is exposed to the house edge. Which brings us to number three.

3. The house edge of the game you play

Every casino game is built to lose you money slowly over time. That is the house edge: the percentage the casino expects to keep from everything you stake. It is the silent cost of clearing a bonus.

It varies massively by game:

• Slots: often around 4% or higher
• Roulette: about 2.7%
• Baccarat and live dealer: roughly 1% to 2.5%
• Blackjack and video poker: as low as 0.5% with correct play

Here is why this is the number that flips a bonus from good to bad. If you have to wager £1,000 to clear a bonus, the game’s edge decides how much of that £1,000 the house expects to take on the way through. At 4% slots, that is an expected £40 cost. At 0.5% blackjack, it is an expected £5. Same bonus, same wagering, but the game you choose changes the maths completely.

4. The game weighting (the one almost nobody checks)

This is the catch hiding behind the headline. Game weighting decides how much each game counts toward your wagering requirement, and it is often nothing like 100%.

Slots usually count 100%. But many casinos count table games at a fraction, sometimes 10% or 25%, and occasionally 0%. So you might spot a low-house-edge game like blackjack and think you have found the smart way to clear a bonus, only to find it contributes 10% toward the requirement. That means to clear £1,000 of wagering you would actually need to stake £10,000 on it. The low edge is useless if the weighting buries you.

The UKGC’s 10x cap did not touch game weighting, so this loophole is still wide open. Always check the weighting table before you commit, not just the headline wagering number.

5. The max win cap and minimum deposit

The last two often get ignored and occasionally ruin an otherwise good offer.

The max win cap is the most you are allowed to withdraw from bonus winnings, regardless of what you actually win. A generous-looking bonus with a tight win cap quietly limits your upside. And the minimum deposit is what you have to put in to qualify, which is real money of your own at risk, so it belongs in the calculation too.

Putting it together: a quick worked example

These numbers are illustrative, to show the method. Always use the real terms of the specific offer.

Say you are offered a £100 bonus, 10x wagering, and you plan to play slots at a 4% house edge with 100% game weighting.

• Total wagering needed: £100 x 10 = £1,000
• Expected cost from the house edge: £1,000 x 4% = £40
• Rough expected value: £100 bonus minus £40 expected loss = +£60

Positive, so on these numbers the bonus is worth taking. Now change one thing: play a game weighted at 25% instead. Your real wagering balloons to £4,000 to clear the same bonus, the expected house-edge cost jumps to £160, and your +£60 becomes a negative expected value. Same bonus. One number turned a good deal into a bad one.

That is the whole point. The headline never tells you. The maths does.

The shortcut

You do not have to do this by hand every time. That is exactly what our bonus calculatoris for. Put in the bonus amount, the wagering requirement, the game, and the house edge, and it returns the expected value in seconds, plus a straight “take it” or “leave it.” Run any offer through it before you deposit, and you are deciding on the numbers instead of the marketing.

Bonuses became fairer in 2026. They did not all become worth taking. Five numbers tell you which is which.

18+ only. Gambling can be addictive. Please play responsibly. If you feel you may have a gambling problem, visit BeGambleAware.org or call the National Gambling Helpline on 0808 8020 133. You can self-exclude from UK-licensed sites via GamStop.

This article is for information only and is not financial advice. Expected value describes long-run averages, not what will happen in any single session, and individual results vary. Bonus terms change without notice, so always check the operator’s current T&Cs. Some links on this site are affiliate links: we may earn a commission if you sign up through them, at no additional cost to you. This does not influence our calculations or rankings.

Questions or corrections? Contact us at bonuscheckeruk@gmail.com.